Welded ship construction



y 7, 1953 a; ALLEGRO WELDED SHIP CONSTRUCTION Filed Dec. 23, 1947 M 0 TL ML VA m a. w G

Patented July 7, 1953 Giuseppe Allegro, Genoa, Italy Application December 23, 1947, Serial No. 793,505

In Italy August 3, 1945 s 7 I zciaims. (Cl. 114-49) e l r In the construction of 'hulls by welding metallic plates, welding of the vertical edges of the plating is accepted by almost all the classification registers, while welding of the horizontal edges of the outside plating in accordance with conventional practice is permitted only by some registers and only in the case of small ships, because such longitudinal weldings leave substantial internal tensions in the material. These tensions, when the ship 'hull undergoes dynamic stresses in heavy seas, cause damage both to the plates and to the welds. Such damage may have serious consequences which may even amount to the loss of the ship.

The object of the present invention is a ship hull construction involving longitudinal and transverse elements supporting the hull plates which have their horizontal edges welded in a.

inga narrower 'face which corresponds to the.

external face of the hull frame; the transverse ribs are connected to each other by means of longitudinal elements and their union is made by welding; each of these longitudinalelements has. a broad face which is disposed in a suitable position relatively to the narrow faces of the transverse ribs; the outside plating'is secured to the hull frame defined by the ribs and the longi-' tudinal elements by welding the corresponding faces of the plates to the longitudinal elements. The invention is characterized by the fact that the transverse ribs are continuous'ribs, the cross section of whichshows an enlargement at itsinner end and a narrow face of uniform width at its outer end; the invention is also characterized by the connection ofthe transverse ribs by means of longitudinal elements which are welded thereto; the ribs are provided with spaced hollows; cuts, and the like, in order to allow the intersection of the longitudinal and transverse elements, so that one of the broader faces of the longitudinal elements will lie in the'same plane with the narrow face of the rib in order to provide a continuous external surface for the reception of the plates.

The invention is particularly characterized by the fact that the longitudinal elements of the hull skeleton have substantially a T-section with their wings disposed in the plane of the narrower face of the ribs and with notches at spaced points along their webs in orderto permit the passage of the transverseribs, the plates being secured to the exterior of the hull skeleton by welding.

The invention is also characterized by the fact that the transverse ribs are formed with shaped cuts at intervals to allow the passage of the longitudinal members. r

- Moreover, generally speaking,.the invention is characterized by the fact that the horizontal edges of the plates are welded together and to the external surface of the longitudinal members, while the longitudinaledges of the wings of said longitudinal members are also welded to the internal surfaces of the plates.

In the annexed drawingsthere is shown an illustrative embodiment of the invention.

Fig. 1 is a partial transverse sectional view of a hull showing the meeting of the edges of two plates;

Fig. 2 is an internal view of a hull of a ship built according to-the present invention;

Fig. 3 is a sectional view taken along the line III-IIIof Fig. 2; V I

Fig. 4 is a perspective view of a portion of a longitudinal element to show details of construction;

Fig. 5-is a similar view of a rib;

Fig. 6 is a perspective view of a portionof Fig. 5toshow details of assembly; and

Fig. '7 is atransverse sectional view of a ship hull constructed in accordance with the invention.

Referring to Fig. l, the contiguous horizontal and longitudinal edges of plates 3 and 4 are placed to correspond to the mid-line of the external face of a longitudinal element of T cross sectionithe edges I and 2 are welded to element 5 by means of welding line 6 and the ends of wings I and 8 are welded to the internal faces of plates 3 and 4 by means of welding lines 9 and it. In this manner, owing to the mass of the longitudinal element 5 during the welding along line 6, the internal tensions of the material are eliminated or reduced to very low values;

tudinal edge an enlargement I2, circular in crosssection, in order to provide the necessary degree of rigidity; the external edge of the rib ends with the full face I3 which at spaced points has a cut I4 in order to facilitate the intersection with the longitudinal elements 5 of the skeleton extending from stem to prow.

It will be understood that the skeleton elements are not affected by the longitudinal bendings of thelongitudinal elements 5, so that the transverse cross section of ribs I I has a constant shape for the entire series of ribs, eliminating thereby the work of bending and twisting.

As may be seen in Fig. 4, the rib I5, of the longitudinal element 5, has cuts [6 allowing the passage of the ribs I I of the skeleton.

While there is no intention of limiting the invention to these details, welding may be provided at the intersection of longitudinal elements 5 and transverseribs II of the skeleton. Fig. 6 shows such an intersection finished by means of the weldingline. I'I, .whilezthe surfaces I3, of the ribs I land. I8 of wings I and 8 of longitudinal element 5, providethe supporting surface for the plate. It must be observed that the preferred embodiment is based on the use of T- shaped longitudinal elements because it has been found that the T-element serves to maintain the plates in position, facilitates the mounting of the frame andmaintainsitin position during the plate mounting andwelding operations, provides support forv the plates during the longitudinal weldin operation, cooperates with theinternal weldings 9 and: III to. reinforce the juncture of the two edges of. the plates, and permits the use on a large. scaleof an automatic welding device in the construction of ships,.thereby eliminating the special devices heretofore considered indispensable. The use of, T-shaped longitudinal elements is of particular importance in reducing the contraction of the longitudinal joints of the plates to negligible values, thereby eliminating the danger of; internal stresses with subsequent deformation-and weld damage.-

Although the invention is based on the illustrative embodiment described above, many modificationsand additions may bemade in the embodiment illustrated and described without departing from the invention. For example, the T elements may be. applied to all or to some of the longitudinal. connections of the plates forming the hull of a ship (bulkheads, decks and so on) thus obtaining advantages analogous to those pointed out above.

Having, now particularly described and ascertained the nature. of my invention and in what manner the same is to be. performed, I declare that what Iclaini is:

1. In a hullof a metallic sea-going ship, in combination, a plurality of transverse ribs, a plurality of elongated longitudinally extending strips. of T-shaped cross-section interconnecting.

said transverse ribs, each of said strips having a longitudinallyextending, flat base. and an up right central web. portion extending inwardly of the hull and being. of a thickness. substantially less thanthe width of. said base, said web being 4 interrupted at intervals to receive said ribs and said ribs being provided with recesses on their outer edges to receive the bases of said strips whereby said ribs and said strips present a flush external surface for reception of hull plates, said transverse ribs being welded to said longitudinal strips, and a plurality of longitudinal hull plates conforming to and positioned against said ribs and strips and ghavingtheir"longitudinal juncture lines coinciding with the centers of the bases of said strips, said hull plates being supported by all of said longitudinally-extending strips and said transverse ribs and conforming to theflush external surface defined by said strips and said ribs, said hull plates being welded to each other alongtheir longitudinal juncture line's and'to thee'dges of said bases but being free from welded connection to said transverse ribs, whereby said plates are free from stress.

2. In a hull of a metallic sea-going ship, in combination, a plurality of transverse ribs, a plurality of elongated longitudinally extending strips of T-shaped cross-section interconnectingsaid transverse ribs, each of said strips having a longitudinally-extending flat base and an upright central web portion extending inwardly of the hull and'being of a thickness substantially less than the width of said base, said web being interrupted at intervals to receive said ribs and said ribs being provided with recesses on their outer edges to receive the bases of said strips whereby said ribs and said strips present a flushexternal surface for reception of hull plates, the opposite edge of said ribs havinga reinforcing bulbous enlargement, said" transverse ribs being welded to said longitudinal stripaand a plurality of longitudinal hull plates conforming to and positioned against s'ai'dribs and strips and having their longitudinal juncture linescoinciding with the centers of the bases of said strips, said hull plates beingv supported by all of said longitudinally-extending strips and said transverse ribs and conforming to the flush external surface defined bysaid strips andsaid ribs, said hull plates being welded to each other along their longitudinal juncture lines and to the edges ofvsaid bases but being free from welded connection to said transverse ribs, whereby said plates arefree' from stress.

cms'eee ALLEGRO.

References Cited in the file of this patent UNITED STATES PATENTS 

